1. Field of the Invention
This invention pertains to a method of packaging hazardous liquids for shipment or containment and to the structure and composition of the packaging which can be used to practice the method.
2. Background Art
The business needs of today frequently require shipment of one or more individual containers of liquid, wherein the individual containers can be as small as a test tube or as large as a bulk container for an industrial chemical (which may be 24 inches in diameter or more). The liquid to be shipped can comprise chemical compounds, synthetic polymers, aromatics, hydrocarbons, biological materials, and radioactive materials, for example. The liquid may comprise a solution, a suspension, or a dispersion, each having different flow characteristics and different reactive capabilities. It is not uncommon that the liquid to be shipped is toxic or contains biologically active or reactive components which present a danger to persons who are exposed to the fluid without the proper protective barrier clothing, eye protection and respiratory equipment.
Even when the packaging in which hazardous liquids are shipped is carefully marked with warnings to alert those who will be handling the shipment to use special care, there is always the possibility the liquid will escape from a package damaged during shipment, exposing those persons handling the package to potential harm. Thus, the packaging in which hazardous liquids are shipped should be capable of preventing the escape of the liquid being shipped and any hazardous vapors thereof.
Inadequacies in existing packaging means recently became apparent when medical doctors searched for packaging which could be used for shipment of blood test kits to outside testing laboratories. The existing shipping method provides for shipping of test tube samples of blood in a formed styrofoam tray which is placed in a gusseted envelope. However, on occasion during shipment, breakage of the test tubes occurs due to rough package handling, causing blood to leak out the edges of the styrofoam tray or cracks or breaks in the tray. Should the blood be contaminated with such as a deadly virus, persons handling the package are thereby exposed to a potentially life threatening hazard. Similar considerations apply to urine specimans, biohazardous fluids in general, and toxic solutions. At this time, the U.S. Postal Service is considering a ban on shipment of disease causing germs or hazardous toxins (etiologic agents).
It is possible to provide packaging which is capable of protecting the liquid container better; it is possible to provide a liquid container which cannot be crushed. Examples of materials which can be used to fabricate such packaging or liquid containers include fiberglass, metals, and reinforced composites of the type commonly used in the chemical industry. However, such packaging or containers are very expensive to manufacture, and reuse requires special tracking during shipment and costly cleaning procedures. The stronger packaging and containers would typically be heavier, increasing shipping costs and making handling more difficult. Containers comprised of fiberglass or metal canisters and bombs are less convenient to use; doctors and nurses prefer tray-form packages for tabletop convenience in laying out tubes of blood and slides.
Examples of subject matter related to the present invention include the United States patents listed below.
U.S. Pat. No. 3,986,914 to Howard, dated Oct. 19, 1976, describes a plastic pouch-like container which is provided with a plastic bead seal at the junction of an interlocking fastener and the side edges of the container. The plastic bead seal acts as a barrier to prevent leakage of fluids or contaminating bacteria through the plastic container in the area adjacent to the fastener/closure of the container.
U.S. Pat. No. 4,267,928 to Curry, Jr., dated May 19, 1981, describes a composite structure container for commercial use in transporting fluids. The container is a composite paper body with a plastic liner forming a structure that is adapted to be sealed with a crimped-on cap, to preserve items stored in the container either under atomspheric pressure, vacuum, or pressurized conditions.
U.S. Pat. No. 4,282,984 to Curry, Jr., dated Aug. 11, 1981, describes a composite container structure similar to that described in U.S. Pat. No. 4,267,928, including use of a resinous tube surrounding the outside of the composite structure, which tube can be shrunk into place over the outer surface of the structure to form a seal.
U.S. Pat. No. 4,495,082 to Mita et al., dated Jan. 22, 1985, describes a water absorbant excellent in water holding capacity under pressure. The absorbant comprises a mixture of a cotton-like material "A" manufactured by a pulping treatment of bagasse containing at least 5 percent by weight of pith and having a lignin content of 5-25 percent by weight and a pulp "B" having a lignin content not greater than 5 percent by weight, wherein the weight ratio of A:B ranges from 95:5 to 20:80.
U.S. Pat. No. 4,572,361 to Fontlladosa, dated Feb. 25, 1986, describes a means for the packing and orderly display of consumer fluid product containers. The means provides for holding the consumer fluid product containers which are of a tube type in fixed, closely packed positions, to prevent damage during shipment.
U.S. Pat. No. 4,597,765 to Klatt, dated July 1, 1986, discloses a method and apparatus for packaging a fluid containing prothesis.
U.S. Pat. No. 4,615,923 to Marx, dated Oct. 7, 1986, describes a water-absorbing insert for food packs. The insert is adapted to be used in direct abutment with food, and comprises an outer covering and an inner filling. The outer covering is pervious to water is is preferably made from an acid-free paper. The filler includes kieselguhr and an organic gel former selected from the group consisting of carboxymethyl cellulose, cellulose ether, polyvinylpyrrolidon, starch, dextrose, gelatin and pectin.
U.S. Pat. No. 4,735,843 to Noda, dated Apr. 5, 1988, describes selectively surface-hydrophilic porous or perforated sheets. The fluid-directed front face of the sheet comprises a hydrophilic perforated surface having a multiplicity of holes for fluid passage. The back face of the sheet is coated with a rubber-like material insoluble in aqueous fluid but having surface-hydrophilic properties, whereby the back face of the sheet is rendered hydrophilic. The sheets are particularly useful as cover sheets for absorbant structures such as diapers, bandages and catamenials.
U.S. Pat. No. 4,738,674 to Todd et al., dated Apr. 19, 1988, describes a method for automatically and continuously indicating wetness of diapers, hospital underpads, and the like, wherein moisture indicator strips of a capillary action type are used to provide a visual indication of wetness at a point removed from the actual point of wetness. A wicking strip is used to transfer the moisture to a moisture indicating substance which visually indicates the presence of moisture.
U.S. Pat. No. 4,738,675 to Buckley et al., dated Apr. 19, 1988, describes a disposable diaper comprising a fluid impervious back sheet, a fluid pervious front sheet, a first absorbant pad adjacent the front sheet and comprising a loosely formed fiberous mass, and a separate second absorbent pad between the first pad and the back sheet. The second pad comprises a mass of fibers having compressed regions extending throughout a substantial part of the second pad and having relatively uncompressed areas adjacent the compressed regions. The compressed regions are used to promote the spreading of fluid throughout the pad, and to direct fluid flow against the force of gravity when the diaper is positioned on the baby.
U.S. Pat. No. 4,740,528 to Garvey et al., dated Apr. 26, 1988, describes an absorbent superwicking crosslinked polyurethane foam composition into which is incorporated an effective amount of at least one amino acid, a one percent by weight aqueous solution of which has a pH of no more than about 8. Said amino acid contains one amino acid group and at least one carboxylic acid group. The polyurethane foam composition is useful as a sponge and in the manufacture of such absorbent composite structures as disposable diapers, incontinent products, etc.
U.S. Pat. No. 4,744,374 to Deffeves et al., dated May 17, 1988, discloses a family of crystalline, microporous silaceous materials of regular geometry which are substantially hydrophobic and which exhibit a stronger affinity for less polar molecules such as ammonia than for water under equivalent exposure conditions. Such silacious materials would be useful in fabrication of filter cartridges for pipes, cigars or cigarettes, and would be expected to absorb significant amounts of carbon monoxide from mainstream smoke more effectively than previously used hydrophilic materials. The hydrophobic material comprises microporous crystalline tectosilicate of regular geometry having aluminum-free sites in a silaceous lattice that are characterized by the presence of about 1-4 associated moieties in said sites of the formula--SiOR, wherein R is a substituent that is a weaker point source than aluminum.
U.S. Pat. No. 4,748,069 to Cullen, dated May 31, 1988, describes a liquid absorbing and immobilizing packet and paper therefor. The packet comprises an envelope which is degradable in the liquid and a liquid absorbing and immobilizing material in the envelope. The liquid absorbing and immobilizing material recommended for aqueous solutions including dilute alkalis, dilute acids, and body fluids is sodium polyacrylate. The envelope can comprise a layer of a liquid degradable material having a patterned coating of sealing material in the layer, wherein the pattern is such that uncoated portions of the envelope remain exposed to be degraded by contact with the liquid.
U.S. Pat. No. 4,748,076 to Saotome, dated May 31, 1988, describes a water absorbent fiberous product comprising a cellulosic material impregnated with a water absorbent acrylic polymer. The fiberous product exhibits a high water absorbency and finds applications as high quality disposable diapers, sanitary napkins, surgical pads, surgical sheets, paper towels or the like.
U.S. Pat. No. 4,748,977 to Guyot et al., dated June 7, 1988, describes a mineral fiber-based absorbent material. The absorbent material is comprised at least partially of mineral fibers which have a specific surface area greater than 0.25 m.sup.2 /g. The fibers have an average diameter under 5 micrometers, having a homogeneous size distribution and are free of non-fibrated or clustered particles. The mineral fiber-based material typically comprises a glass fiber.
U.S. Pat. No. 4,753,643 to Kassai, dated June 28, 1988, describes a disposable diaper. The disposable diaper comprises an inner member to be in contact with the skin of a wearer, an outwardly directed member, and an absorbent member interposed between the same. Baby powder is retained in a pulverulent state in cavities or wrinkles defined in the inner member by gathers.
U.S. Pat. No. 4,753,834 to Braun et al., dated June 28, 1988, discloses a nonwoven web with improved softness, tensile strength, and tear resistance. The nonwoven web comprises monofilaments or fibers of a thermoplastic material, wherein the improvement comprises the use of monofilaments or fibers which have a bilobal-shaped cross section.
U.S. Pat. No. 4,758,239 to Yeo et al., dated July 19, 1988, describes a breathable barrier. The barrier includes a first layer which is a porous sheet having a first side and a second side. A second layer is joined to the first side of the first layer, which second layer is a continuous film of a water soluble polymeric material, in which the film is not micorporous in that it is substantially free of voids which connect the two surfaces of the film. Water molecules are capable of being transported through the second layer film as a result of the solubility of the water molecule in the polymeric material. The second layer film has an average thickness of from about 3 to about 250 microns. The first layer side of the second layer film is intimately comingled with at least some of the fibers at the surface of the first side of the first layer, and none of the pores at the surface of the first side of the first layer are so large as to significantly adversely affect the barrier properties of the breathable barrier as a consequence of the comingling.
There are additional patents related to adsorbent and absorbent materials, to immobilizing additives and compounds and to the structure of multilayer sheets and pads designed to utilize such materials, additives, and compounds. The above-cited U.S. Patents are offered as examples closely related to the subject matter of the present invention. The relationship of such subject matter to the present invention will become more apparent upon reading the summary and detailed description of the present invention.
The problem of hazardous liquid leaking from a package to expose those not equipped or trained to handle such liquids can be greatly reduced or eliminated by shipping the hazardous liquid in a package designed to prevent the liquid or hazardous vapors thereof from penetrating the exterior of the package should a container inside the package fail during shipment. There is a need for a package means which accomplishes this goal in a relatively inexpensive manner.
There is also a need for a package which can be used to contain a known hazardous liquid leakage, such as a leak from industrial pails or drums. The kind of package which can be used for shipping of hazardous liquids can also be used for containment of such leaking vessels by techniques such as shrouding the leaking vessel in the package, inverting, and then sealing the package.